Dielectric multiphase flow meter

Abstract

A sensor is provided for detecting relative amounts of components within a mixture. The sensor includes a dielectric transducer comprising a first conductive rod and a second conductive rod; an oscillator configured to apply a voltage to the first conductive rod; an amplifier configured receive a voltage from the second conductive rod as input; and a controller configured to periodically sample an output voltage of the amplifier to generate a plurality of sample voltages, compare the sample voltages against distinct voltage values for identifying each of the components to determine the relative amounts of the components.

What is claimed is: 
     
       1. A sensor for detecting relative amounts of components within a mixture, the sensor comprising:
 a dielectric transducer comprising a first conductive rod and a second conductive rod; 
 an oscillator configured to apply a voltage to the first conductive rod; 
 an amplifier configured receive a voltage from the second conductive rod as an input; and 
 a controller configured to periodically sample an output voltage of the amplifier to generate a plurality of sample voltages, compare the sample voltages against distinct voltage values for identifying each of the components to determine the relative amounts of the components, 
 wherein the first conductive rod includes a first angled front side disposed at a first acute angle relative to a first back side of the first conductive rod, the second conductive rod includes a second angled front side disposed at a second angle relative to a second back side of the second conductive rod, the first and second angled front sides face each other, and the mixture flows through a space between the first and second front angled sides. 
 
     
     
       2. The sensor of  claim 1 , wherein the controller determines the relative amounts of the components by integrating the relative amount of time each component was identified. 
     
     
       3. The sensor of  claim 1 , wherein the first conductive rod includes a first portion below the first angled side and a second portion below the second angled side, and the dielectric transducer includes a three-layer region between the first and second portions, the three-layer region including a first insulator covering a first side of the first portion, a second insulator covering a second side of the second portion, and a conductive sheet between the insulators that is grounded. 
     
     
       4. The sensor of  claim 3 , wherein the first and second sides are flat and the back sides are semi-conical. 
     
     
       5. The sensor of  claim 1 , wherein the amplifier is designed so that its output voltage is a first voltage value among the distinct voltage values to indicate oil, a second voltage value among the distinct voltage values to indicate gas, and a third voltage value among the distinct voltage values to indicate water. 
     
     
       6. The sensor of  claim 1 , further comprising a phase comparator configured to operate on the voltage applied by the oscillator and the output voltage of the amplifier to determine a phase difference, wherein the controller uses both the output voltage and the phase difference to determine a given one of the components of the mixture. 
     
     
       7. The sensor of  claim 6 , wherein the controller determines the given one component is oil when the output voltage is a first voltage value among the distinct voltage values and the phase difference is 90 degrees and the controller determines the given one component is a mixture of water and gas when the output voltage is the first voltage value and the phase difference is less than 90 degrees. 
     
     
       8. The sensor of  claim 7 , wherein the controller determines the given one component is gas when the output voltage is a second voltage value among the distinct voltage values and the phase difference is less than 90 degrees and the controller determines the given one component is a mixture of water and oil when the output voltage is the second voltage value and the phase difference is less than 90 degrees. 
     
     
       9. The sensor of  claim 8 , wherein the controller determines the given one component is water when the output voltage is a third voltage value among the distinct voltage values. 
     
     
       10. The sensor of  claim 1 , further comprising a variable capacitor connected to the input of the amplifier, wherein the voltage applied by the oscillator to the first conductive rod has a positive polarity, and the oscillator applies the voltage of a negative polarity to the variable capacitor. 
     
     
       11. A dielectric flowmeter comprising:
 a first dielectric transducer comprising a first pair of conductive rods, a first oscillator configured to apply a first voltage to a first conductive rod of the first pair, a first amplifier configured receive a voltage from a second conductive rod of the first pair as an input; 
 a second dielectric transducer comprising a second pair of conductive rods, a second oscillator configured to apply a second voltage to a first conductive rod of the second pair, a second amplifier configured receive a voltage from a second conductive rod of the second pair as an input; and 
 a controller configured to determine a flow rate from an output of the first amplifier and an output of the second amplifier, 
 wherein each of the first conductive rods includes a first angled front side disposed at a first acute angle relative to a first back side of the corresponding first conductive rod, each of the second conductive rods includes a second angled front side disposed at a second angle relative to a second back side of the corresponding second rod, the first and second angled sides of the first pair of conductive rods face each other across a first space, the first and second angled sides of the second pair of conductive rods face each other across a second space, and the mixture flows through the first space and the second space. 
 
     
     
       12. The flowmeter of  claim 11 , further comprising a spool, wherein the first pair of conductive rods are inserted into an interior of the spool at a first position, and the second pair of conductive rods are inserted into the interior at a second position. 
     
     
       13. The flowmeter of  claim 12 , wherein the spool includes a hollow tube, and each of the conductive rods are inserted into the tube. 
     
     
       14. The flowmeter of  claim 11 , where each pair of conductive rods includes a three-layer region between the corresponding first and second conductive rods, the three-layer region including a first insulator covering a first side of one of the corresponding first and second conductive rods, a second insulator covering a second side of the other one of the corresponding first and second conductive rods, and a conductive sheet between the first and second insulators that is grounded. 
     
     
       15. The flowmeter of  claim 11 , wherein each amplifier is designed so that its output voltage is a first voltage value to indicate oil, a second voltage value to indicate gas, and a third voltage value to indicate water, wherein the first, second, and third voltage values differ from one another. 
     
     
       16. The flowmeter of  claim 12 , wherein the first dielectric transducer includes a first buffer storing first values generated from outputs of the first amplifier, and the second dielectric transducer includes a second buffer storing second values generated from outputs of the second amplifier. 
     
     
       17. The flowmeter of  claim 16 , wherein the controller generates a first pattern from the first values, generates a second pattern from the second values, and determines the flow rate when the first pattern is similar to the second pattern by subtracting a time the second pattern is detected from a time the first pattern is detected to generate a travel time and dividing a distance between the first and second positions by the travel time. 
     
     
       18. The flowmeter of  claim 12 ,
 wherein the first dielectric transducer filters out outputs of the first amplifier having a certain phase difference with the first voltage, 
 wherein the second dielectric transducer filters out outputs of the second amplifier having the certain phase difference with the second voltage, and 
 wherein the controller determines the flow rate from the remaining outputs of the first amplifier and from the remaining outputs of the second amplifier.